How far down the abstraction tree do you go before something is 'pure'? Programming on the whole is at a much higher abstraction level than ever. Maybe what p

How far down the abstraction tree do you go before something is 'pure'? Programming on the whole is at a much higher abstraction level than ever. Maybe what people are really looking for is simplicity, but this changes depending on the complexity of your project. Therefore the question becomes, "What is the best level of abstraction for this project?" That changes every time you do something new.